Treating hydrocarbon fluids



INVENTOR 03577' f.' RUT//HUFF ma 5 ATTORNEY N. uw

R. F. RUTHRUFF TREATING HYDROCARBON FLUIDs Filed June 6. -1939 July 1944.

containing gasoline constituents.

Patented July 11, 1944 UNITED f STATES PATENT OFFICE TREATING HYDaooAnBoN rLUlns Robert F. nummer, Hatley, N. J. Application June s, 1939, serial No. 277,530

(ci. 19a- 52)- 11 Claims.

This invention relates to the treatment of hydrocarbons and is especially adapted for convert-v ing higher boiling hydrocarbons to lower boiling hydrocarbons.

According to my invention a relatively heavy hydrocarbon liquid io be converted, such as heavy gas oil, is heated and passed through one catalyst in a catalyst chamber to preferentially or selectively convert the higher boiling hydrocarbons of the charge into products of intermediate boiling range. This catalytic treatment includes dehydrogenation and prepares the hydrocarbon components for conversion in contact with a second catalyst in a later step in the process. same time some lighter components within the gasoline'boiling range are formed but the action At the of the catalyst is to mainly convert the heavy ends of the hydrocarboncharge without attacking and converting the lighter components thereof.v The catalytic conversion is preferably carried out un- 4der normal 'atmospheric pressure conditions but higher or lower pressures may be used.

After passing in contact with the first catalyst,

Or the prodand passed through a second heated catalyst in a catalyst chamber for further catalytic treatment under substantially normal atmospheric pressure. but higher or lower pressures maybe used. The second catalyst preferably comprises a catalyst which acts to convert substantially all the'components of the lighter condensate oil with the production of larger amounts of gasoline than the amounts obtained in the first catalytic treatment and accompanied by relatively little change in the end point of the converted condensate oil. However, the end pointof the converted condensate oil is somewhat lower than the end point of the unconverted condensate oil charge.

'I'he products of conversion leaving the second catalyst chamber are fractionated to separate.

condensate oil from light hydrocarbon vapors The condensate oil may be removed as a product from the systemand passed to storage or -it may be recycled vthrough the second catalyst for further treatment. The productsv of conversion leaving the second catalyst chamber may be cooledto separate liquid from vapors and the liquid distilled to separate gasoline constituents from higher boiling gas-oil or wax distillate, such as, for example, one

having an A. P. I. gravity of about 25.22 and an initial boiling point of about 634 F., and 90% off at about 755 F., is passed through line I0 by pump l2 and through heater I4 in furnace I6 where it is heated to about 700 F., to 1000 F., preferably about 850,F., under normal atmospheric pressure and is substantially completely vaporized. Any unvaporized liquid can be removed in any suitable manner. vThe vapors are then passed through line I8 Iand introduced into a catalyst container 20 provided with catalyst material 22. rI'he vapors are passed through the vcatalyst material and remain in contact therewith for a sulcient length of time to effect the desired extent of conversion. The catalyst, at the beginning of the operation, is preferably preheated to the temperature' of the vapors which are to be treated.

The catalyst 22 is one which selectively converts the heavier constituents of the charging oil stock into lower boiling constituents or into products of intermediate boiling range without converting any substantial amounts of the lighter constituents of the charging oil stock and without much production of lower boiling constituents in the gasoline boiling range. The preferred catalyst for this conversion is lead zinc chromite mounted on magnesia as a support. If desired, the magnesia support may be omitted. The catalyst 22 is made up of pieces of such size and shape that with the catalyst in position in the catalyst container 20, lthe vapors will be able to pass fairly freely through the catalyst and between the catalyst particles, the catalyst at the same time affording suiiicient contact surfaces.

The preparation of lead zinc chromite on magnesia as a support will now be given. About 300 cc.- of magnesla consisting of small pieces of about pea size are added to about 188 cc. of

inportions to form the chromite catalyst.

ammonium containing 0.25 mol of chromium. lThis solution is" prepared by dissolving about 168 g. of ammonium dlchromate in about 600 cc. of water, adding about 250 cc. of ammonia and then diluting to about 1000 cc.

'I'he support is preferably saturated by the vacuum method by introducing the support and the ammonium chromate solution into a flask Ior other container which .is evacuated in any suitable mannenas by avacuum pump. and any air'f' heated for about one hour byvplaclng it on a water bath or similar heating means, after which the container is removed.

About 180 cc. of a solution containing 0.225 mol lead (as lead nitrate) and 0.225 mol zinc (as zinc nitrate) are heated to 4about 175 F. and added with stirring to the hot support-ammonium chromate solution described above. By this operation the support is covered with an adherent layer of 'lead zinc chromate, additional material remaining in suspension. The support is removed from the solution and drained and the supported lead zinc chromate is then air dried at about 125 F.

To convert the lead zinc chrcmate to lead zinc chr-omite, I prefer to place a portion ofthe supported chromate in a porcelain dish which is heated by keeping a burner in constant motion and during heating the supported chromate is stirred continuously. At rst some water is evolved, after which decomposition begins with the evolution of fumes. I'he decomposition is complete when'fumes are no longerevolved and the catalyst is of uniform color. The rest of the supported chromate catalyst is similarly treated r the whole batch of the chromate catalyst may be treated but care must be taken not to overheat the catalyst undergoing treatment.

The supported chromite catalyst is then leached for several hours with about 600 parts byvolume of acetic acid and then drained. The chromite catalyst is then repeatedly washed with water and then air dried at about 125 C. The

supported lead zinc chromite catalyst is then ready for use and is placed in tainer 20.

The treated vapors after contact with the catalyst` 22 are passed through line 24 into the bot` tom portion of a fractionatingtower 25 to separate relatively heavycondensate oil from lighter hydrocarbon vapors. The fraetlonatlng tower has a trap out tray 2l for collecting lighter condensate oil which is withdrawn and passed throughA Aof collected ontrap out tray 26 for passage to the second catalyst chamber 2l instead of being iirst passed through the first catalyst zone 2l. 'I'he heaviest components of the charge oil together with unconverted heavier components will the catalyst conl withdrawn and recycled line 20 by Pump Il. v

If desired the trap out tray 2l may be omitted and condensate oil withdrawn from the bottom of tower 25 may in part be recycled to heater I4 and in part passed to heater Il. Y

The vapors remaining after fractionation in the fractionating tower 25 leave the top thereof vthrough line I2 and are passed through condenser I3 to condensate the normally liquid constituents yand passed to a separator I4 provided with a valved liquid outlet 38 and a valved gas outlet 30 to separate liquid containing-gasoline constituents from gases.

' Instead of passing the vapors to the fractionating tower 25, they may be cooled to condense normally liquid constituents to separate them from gases and the normally liquid constituents lcan be separately distilled to separate lighter hydrocarbons boiling of! below about 400 F. from higherboilingr constituents. In this way a wax distillate having the above mentioned characteristics and with 90% off at a temperature of 755 F., was passed over catalyst 22 and the liquid separated from the conversion products was distilled. The percentage by volume of lighter constituents boiling oi up to about 400 F. was about 10% and the temperature at 90% off was about 655 F. From this it will be seen that the higher boiling components were converted to intermediate boiling components without producing lmuch lighter components within the gasoline boiling range.

.The lead zinc chromite catalyst is a dehydrogenating catalyst and the gas produced during Y the conversion contains mainly hydrogen. The

gas also contains methane and small amounts of C: and C3 hydrocarbons.'

A portion orl all of the relatively heavy conproduct. and passed to storage. Fresh charging be'collected on the bottom of the tower 25 and 75 oil from an extraneous source may be passed through line 40 and admixed with the condensate f oil passing through line 21. Or condensate oil from trap out tray 28 maybe mixed with gasoline from separator 24 and the mixture passed through line 21 and second catalyst chamber 2l for further conversion treatment. v

'I'helighter condensate oil from trap out tray 28 is passed through line 21 by pump 43 and is heated and substantially completely vaporized in heating zone. in heater 45 and the vapors arepassed through line 5l and introduced into the second catalyst chamber 28 containing catalyst The catalyst 58 in chamber 28 is different from catalyst 22 and is one which does not selectively convert the higher boiling hydrocarbon constituents of the oil charge but acts to convert substantially vall of the hydrocarbon constituents of the oil vapors to produce a larger percentage of relatively'light vapors containing gasoline conv stituents than the iirst mentioned catalyst.y

The end point of the oil passing through catalyst 58 is lowered a relatively' small amount so that the end point of the treated oil will be slightly lower than the end pointof the hydrocarbon oil charge introduced into the heating zone 4l.

The catalyst 50 which I use in the second catalyst chamber 28 i's a clay, preferably one having a silica to alumina weight ratio of about 4 to i, but other catalysts may be used which act'to produce large percentagesof lighter hydrocarbons containing gasoline components. The clay to the heater llthrough s may be a naturalclay treated to obtain the desiredratio of silica to alumina or the clay may be synthetically prepared.

The lighter condensate loil which is passed through the catalyst 58 is heated to about 700 to 1000 F., preferably about 850 F., and under ing hydrocarbons in the gasoline boiling range are obtained.

The hydrocarbon vapors after passing through the clay or other catalyst 58 are passed through line 60 to a fractionating tower 62 to separate condensate oil from lighter vapors, the lighter vapors passing overhead through line 64 and then 'to condenser 6B to condense normallyjlquid constituents containing gasoline constituents. The liquid and gases lare passed to a separator having a valved gasoutlet 12 vand a valved liquid outlet 14 to separate normally liquid hydrocarbons within the gasoline boiling range from gases. The gases contain C2, Ca and C4 hydrocarbons and are low in hydrogen. .A larger percentage of liquid hydrocarbons within the gasoline boiling range is obtained and withdrawn throughline 14 than is obtained in the first catalytic step at 22 and removed from separator 315 through line 38. v

The condensate oil is withdrawn from the bottom of the fractionating tower 62 through line 'I8 and may be recycled through lineA 80 to the second 'heating zone te and then through the second catalyst chamber 28. Or a portion or all of the condensate oil may. be withdrawn treated as desired'.

Instead of passing the converted vapors to Y the fractionating tower 62, they may be cooled'to separate normally liquid constituents from normaily gaseous constituents. For example, the condensate oil withdrawn from tray 28 in tower 25 or passing through the second catalyst 5 8 may have an initial boiling point of about 450 F., and an end pointy of about 750 F. and this condensate oil is heated and passed through catalyst 58. The liquidseparated from the products 'of conversion leaving catalyst 58 when distilled shows that the percentage by volume of lighter constituents boiling off up to about 400 'F. was about 50%. The results above given with re' spect to catalyst 22 and 58 relate to once-through operations.

For the catalyst in catalyst container I 'prefer to use a chromite s electedfrom the group, lead zinc chromite, copper barium chromite and used to make the copper barium chromite catalyst following the steps given in the method of preparing lead zinc chromite.v For the nickel barium chromite the heavy metal solution contained 0.225 mol nickel (as nickelnitrateland 0.025 mol barium (as barium nitrate).

To prepare the molybdenum sulfide catalyst alumina was saturated with ammonium thiomolybdate preferably by the vacuum. method after which the material was air dried. On gentle heating ammonium thiomolybdate decomposesv to formv molybdenum sulfide. The catalystsl may be usedwith supports suc as alumina, magnesia, synthetic clays containing silica. and alumina, promoted synthetic clays, natural clays, activated natural clays, and the like orv the catalysts may be used without supports.

In passing the hydrocarbon' oil charges over thelfirst and second catalysts, each hydrocarbon charge is passed over about 220 cc. of each catay lyst at the rate of about 85 cc. per hour. I am not to be limited to these figures -as they are given Y merely by way of example.

Suitable reflux is provided for fractionating towers and 62. I

While my invention has been specifically described as a two stage process for converting hydrocarbons, it is not .to be limited thereto, as the preferred group of catalysts, lead zinc chromite, nickel barium chromite and copper bariulm chromite, may be used in a one-step process where higher molecular weight hydrocarbons are to be converted to lower molecular weight hydrocarbons nickel barium chromite, and in this group lead zinc chromite is the preferred catalyst; but other catalysts such as metallic nickel or molybdenum sulfide (M053) may be used. If desired, the catalysts may be used on alumina or other supports or without supports. 'Ihe complex chromite compounds may be made in the same way as described in the preparation of lead zinc chromite except that different metal solutions are used and of course alumina particles are used as a support rather than magnesia particles. For example, 0.225 mol copper (as copper nitrate) and 0.025 mol barium (as barium nitrate) were including gasoline, the lower molecular Weight hydrocarbons including gasoline being withdrawn from separator 34 and the condensate containing higher molecular weight hydrocarbons being withdrawn through line 48 to be passed to'storage or to be further treated as desired.

While I have given examples of catalysts and have included certain conditions for purpose of illustration, I am not to be restricted thereto as changes and modifications may be made within the scope of my invention.

, This application is acontinuation in part of my copending Application Serial No. 205,442, led lMay 2, 1938. f

tial amounts of gasoline constituents but with the l formation bf a -gas product containing mainly hydrogen.

2; The process of claim l1 wherein said dehydrogenating catalyst comprises lead zinc chromite.

3. The process 'of claim 1 wherein said dehy- I drogenating catalyst comprises lead zinc chromite supported on magnesia.

4. rlhe process for treating hydrocarbons to produce lower boiling hydrocarbons which com prises contacting a relatively heavy hydrocarbon oil in the vapor phase with a dehydrogenat` ing catalyst comprising lead zinc chromite under conditions of temperature, pressure and time suitable to eiiectsubstantial `cracking of said oil to 4 A assaess lower boiling products boiling above the gasoline boiling range without the formation oi substantial amounts of gasoline constituents, separating from the products of said cracking operation a relatively light condensate oil boiling above the gasoline boiling range, and contacting said light oil with a cracking catalyst under conditions of pressure, temperature and time suitable to eifect substantial conversion of said light oilto lower boiling products within the gasoline boiling range.

5. The process for treating hydrocarbonsv to produce lower boiling hydrocarbons which comprises contacting a relatively heavy hydrocarbon oil in the vaporlphase with a dehydrcgenating catalyst comprising lead zinc chromite supported on magnesia under conditions of temperature, pressure and time suitable to eil'ect substantial cracking of said oil to lower boiling products boiling above the gasoline boiling range without the formation oi` substantial amounts of gasoline constituents.- separating from the products of said cracking .operation a relatively light confdensateI oil boiling above the gasoline boiling to eilect substantial cracking of said oil to lower boiling normally liquid products boiling predominantly above the gasoline boiling range and be-vv low the boiling range ci said heavy oil, fractionating the products of said conversion treatment to separatetherefrom a light fraction comprising gasoline constituents, a heavy fraction compris- .ing a relatively heavy oil 'and an lintermediate fraction consisting of a relatively light condensate having a boiling range substantially lower than that of said first-mentioned heavy oil, and contacting said light condensate oil with a cracking catalyst in the absence of either oi said relatively heavy hydrocarbon oils under conditions of pressure, temperature and time suitable to eiect substantial conversion of said light oil to lower boiling products within the gasoline boiling range.

'1. A process in accordance with claim 6 wherein said relatively heavyhydrocsrbon oil is contacted with a dehydrogenating catalyst supported on magnesio. l

v8. A process in accordance with claim 6 wherein said relatively heavy hydrocarbon oil is contacted with e dehydrogenating catalyst supported `on alumina.' l

9. The process fortreating hydrocarbons to produce lower boiling hydrocarbons whichlcomprises contacting a relatively heavy hydrocarbon oil in the vapor phase with a dehydrogenating catalyst under conditions of temperature. pressure and time suitable to effect substantial crackingoi'sailoiltolowerboilingnormsllyliquid products boiling predominantly above'the gasoline boiling range and below the boiling range of seid heavy oil, i'ractionatlng the products of'ssid' con` version treatment to separate therefrom a light fraction comprising gasoline constituents. aheavy fraction comprising a relatively heavy oil and an intermediate fraction consisting of arelatively light condensate oil boiling above the gasoline boiling rangeand having a boiling range substantially lower than that of said nrstemmitioned heavy oil, and contacting said light condensate oil with a cracking catalyst in the absence-of either oi' said relatively heavy hydrocarbon oils under conditions of pressure, temperature and time suitable to effect substantial conversion ot said light. oil to lower boiling products within the gasoline boiling range.

10. Thev process for treating hydrocarbons to produce lower boiling hydrocarbons which comprises contacting a relatively heavy hydrocarbon oil with a dehydrogenating catalyst comprising a heavy metallic chromite selected from thergroup consisting of lead zinc chromite, copper barium chromite and nickel barium chromite under conditions of temperature, pressure and-time suitable to eiect substantial cracking of said oilto lower boiling lnormally liquid products boiling predominsntly above the gasoline boiling range and below the boiling range oi' said heavy oil, fractionating the products of said conversion treatment to separate therefrom a light fraction comprising gaso-i line constituents, a heavy fraction comprising a relatively heavy oil and an intermediate fraction' consisting of a relatively light condensate oil boiling above the gasoline boiling range and having a boiling range substantially lower than that oi' said mst-mentioned heavy oil, and contacting said oil boiling above the gasoline boiling range and y lilht condensate oil with va cracking catalyst in the absence of either of`said relatively heavy hydrocerbcn oils under conditions of pressure, tem-v perature and time suitable to effect substantial conversion of said light pil to lower boiling prod-- ucts within the gasoline boiling range.`

chromite, copper barium chromite and vnickel Alili barium chromite under conditions of temperature. pressure and time suitable to eifect substantial cracking of said oil to lower boiling normally liquid products boiling predominantly above the gasoline boiling range and below the honing range of said heavy oil, frsctionating the products of said conversion treatment to separate therefrom a light fraction comprising gasoline constituents. a heavy fraction comprising a relatively heavy oil and en intermediate fraction consisting oi' a relatively light condensate oil boiling aboveV the gasoline boiling rangeand having a boiling range substantially lower than that of said nrst-mentlcnedheavy oil. and contacting said light condensate oil with .a cracking catalyst in `the sbeence of either of said relatively heavy hydrocarbon oils under conditions oi pressure. tempersture and-time suitable to elect substantial conversion of said light oil to lower boiling .products within thegesoline boiling range. 

